$ git clone -n https://src.fedoraproject.org/rpms/pbuilder.git /var/lib/mock/f45-build-21444-584/root/chroot_tmpdir/scmroot/pbuilder
Cloning into '/var/lib/mock/f45-build-21444-584/root/chroot_tmpdir/scmroot/pbuilder'...
$ git fetch origin 315b78207d7f55148fd1dff576e0b62ca7bbce28:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/pbuilder
 * [new ref]         315b78207d7f55148fd1dff576e0b62ca7bbce28 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 315b782 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild